[Show abstract][Hide abstract] ABSTRACT: microRNAs (miRNA) are involved in many biological processes. They repress target gene expression and play a vital role in breast invasive carcinoma (BRCA). Although many miRNAs are identified to be aberrantly expressed in BRCA and deemed as tumor markers, only sporadic individual studies report their target genes and the pathways involved.
[Show abstract][Hide abstract] ABSTRACT: Monoclonal antibodies (mAbs) complex pharmacokinetic (PK) properties including a nonlinear pharmacokinetics and a significant variation in individual PK process cannot be appropriately described by classic PK models, probably derived form a poor understanding of the complex elimination of mAbs. In this study, a novel PK model based on mAbs' complex drug elimination was established. Subsequently, this new model was used to fit bevacizumab plasma concentration data from PK rabbits, and the outcomes of model fitting were compared with those came from a fit with classic models. In addition, the variations existing in the parameters set in the new model were analyzed. As a result, this novel model reasonably described the single-dose PK profiles of bevacizumab in rabbits, and its fitting efficiency was greatly improved compared with those fitted with classic PK models in terms of the weighted residual sum of squares. Moreover, the variations existing in the new model's parameters CA(antibody) and K0 could reasonably explain the individual variations of bevacizumab's PK profiles. In conclusion, the novel model reasonably explained the elimination of bevacizumab, and exhibited a potential as a useful tool for the PK studies of bevacizumab and other mAbs in practice.
No preview · Article · Feb 2016 · International immunopharmacology
[Show abstract][Hide abstract] ABSTRACT: As a new antitumor drug, simotinib hydrochloride is prescribed for prolonged periods, often to patients with comorbidities. Therefore, the risk for developing drug resistance and drug-drug interactions between simotinib and other agents has to be taken into consideration. As P-glycoprotein (P-gp) is an efflux transporter, which plays a significant role in drug resistance and influences the pharmacological properties and toxicities of the drugs it interacts with, the interactions between simotinib and P-gp were investigated. Cytotoxicity was measured using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Intracellular drug concentrations were detected by high-performance liquid chromatography, fluorescence-activated cell sorting and using a fluorescence reader. P-gp ATPase activity was measured using the Pgp-Glo assay, and intracellular pH was assessed using the fluorescent probe 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl. The expression and transcription of P-gp were detected by western blotting and the luciferase assay. Simotinib has no cross-resistance to P-gp substrates, and its efflux rate was independent of either the P-gp expression or the coadministered P-gp substrate. Simotinib reversed chemotherapeutic agent resistance in a short time by increasing the intracellular concentration of the chemotherapeutic agent and blocked rhodamine 123 efflux. Further studies demonstrated that simotinib inhibited P-gp activity by modulating its ATPase activity and the intracellular pH. Although simotinib induced P-gp expression after extended treatment, the induced expression of P-gp had little impact on drug resistance. Simotinib is not a substrate of P-gp. As a modulator, it functions mainly as an inhibitor of P-gp by modulating the intracellular pH and ATPase activity, although it also induces P-gp expression after extended treatment.
Full-text · Article · Jan 2016 · Anti-cancer drugs
[Show abstract][Hide abstract] ABSTRACT: An endogenous CYP3A4 biomarker for in vivo metabolism of cyclosporine should be useful for optimizing individual dosage. We aimed to investigate if the combined ratio of endogenous 6 beta-hydroxycortisol and 6 beta-hydroxycortisone to cortisol and cortisone (HOM) in urine could be used as an endogenous probe for the prediction of cyclosporine dosage requirements in renal transplant recipients. 54 medically stable kidney transplant recipients participated in this study. Morning spot blood and urine samples were gathered. The multiple regression analysis including urinary HOM and body mass index accounted for 73.1% of variability in blood concentration/dose ratio (C/D) of cyclosporine, in which urinary HOM and body mass index contributed 64.9% and 8.2%, respectively. Based on the present approach, individual dosage regimen of CsA could be acquired without therapeutic drug monitoring and the results showed that all of the observed stable doses of CsA were within the predicted range during different post-operative periods. In summary, there is a significant relationship between endogenous CYP3A4 biomarker (assessed by urinary HOM) and in vivo metabolism of cyclosporine in renal transplant recipients. Urinary HOM and body mass index are important predictors of cyclosporine metabolism. Our findings provide clinical implications that the predictive algorithm based on a simple, safe and non-invasive CYP3A4 phenotyping can be anticipated.
[Show abstract][Hide abstract] ABSTRACT: Etanercept is the first tumor necrosis factor inhibitor to be approved for rheumatic disease treatment. Its in vivo concentration is usually detected with commercial enzyme-linked immunosorbent assay (ELISA) kits; specifically, previous researchers have mostly used double-antibody sandwich ELISA technology. Double-antibody sandwich ELISA is employed to detect the total etanercept rather than biologically active etanercept, which is more relevant in terms of therapeutic drug monitoring. In this work, a sensitive ELISA that employed its antigen TNF-α to capture biologically active etanercept for concentration detection was established and validated for etanercept pharmacokinetic (PK) study in patients with ankylosing spondylitis (AS). The proposed assay was demonstrated to be precise and accurate over the linear range of 12.5-400. pg/mL. The intra- and inter-assay relative standard deviation ranged from 3.9 to 12.2% and 6.2 to 11.1%, respectively, and recovery varied between 90.1 and 99.7%, confirming the assay's reliability. The effectiveness and accuracy of the assay was also validated according to quality samples containing etanercept with different TNF-α concentrations, and with plasma samples from patients with AS. To complete the study, both the proposed assay and double-antibody sandwich ELISA were applied to the PK study of etanercept in patients and compared. The multiple-dose results of both analytical methods were consistent, while the drug exposure of the first dose as-detected by the proposed assay was lower than that detected by double-antibody sandwich ELISA. In conclusion, the proposed ELISA was shown to provide more accurate concentration data for therapeutic drug monitoring in comparison to commercial ELISA kits.
No preview · Article · Dec 2015 · Journal of chromatography. B, Analytical technologies in the biomedical and life sciences
[Show abstract][Hide abstract] ABSTRACT: A simple and specific HPLC-UV method was developed and validated for the determination of SM-1 in rat plasma. The bioanalytical procedure involved extraction of SM-1 and gefitinib (internal standard, IS) from a 100 μL plasma aliquot with simple protein precipitation with methanol. Chromatographic separation was achieved using an Agilent TC-C18 column (4.6 mm × 150 mm, 5 μm) with an isocratic mobile phase consisting of 10 mM potassium hydrogen phosphate solution (pH 7.0, adjusted by using 10% phosphoric acid)-acetonitrile (37:63, v/v) at a flow-rate of 1.0 mL min-1. The UV detection wavelength was 282 nm. SM-1 and IS eluted at 3.6 and 7.0 min, respectively, with a total run time of 8 min. Method validation was performed according to US Food and Drug Administration bioanalytical guidelines and the results met the acceptance criteria. The calibration curve of SM-1 in rat plasma was linear over the concentration range of 0.1-20 μg mL-1. Intra- and inter-run precisions of SM-1 were less than 6.1% and the biases were within ±10.0%. The method was successfully applied to the pharmacokinetics study after intravenous and oral administration of SM-1 in rats.
No preview · Article · Nov 2015 · Analytical methods
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to apply the reference-scaled average bioequivalence (RSABE) approach to evaluate the bioequivalence of 2 formulations of agomelatine, and to investigate the pharmacokinetic properties of agomelatine in Chinese healthy male subjects. This was performed in a single-dose, randomized-sequence, open-label, four-way crossover study with a one-day washout period between doses. Healthy Chinese males were randomly assigned to receive 25mg of either the test or reference formulation. The formulations were considered bioequivalent if 90% confidence intervals (CIs) for the log-transformed ratios and ratio of geometric means (GMR) of AUC and Cmax of agomelatine were within the predetermined bioequivalence range based on RSABE method. Results showed that both of the 90% CIs for the log-transformed ratios of AUC and Cmax of 7-desmethyl-agomelatine and 3-hydroxy-agomelatine were within the predetermined bioequivalence range. The 90% CIs for natural log-transformed ratios of Cmax, AUC0–t and AUC0–∞ of agomelatine (104.42–139.86, 101.33–123.83 and 97.90–117.94) were within the RSABE acceptance limits, and 3-hydroxy-agomelatine (105.55–123.03, 101.95–109.10 and 101.72–108.70) and 7-desmethyl-agomelatine (104.50–125.23, 102.36–111.50 and 101.62–110.64) were within the FDA bioequivalence definition intervals (0.80–1.25 for AUC and 0.75–1.33 for Cmax). The RSABE approach was successful in evaluating the bioequivalence of these two formulations.
[Show abstract][Hide abstract] ABSTRACT: The edge effect in enzyme-linked immunosorbent assay (ELISA) affects bevacizumab plasma concentration detection with a higher absorbance of the wells at the edges of plates. Moreover, an inappropriate model fitting with classic compartment models also makes it hard to perform accurate pharmacokinetic (PK) studies for bevacizumab. In this work, an ELISA using a new method to control the edge effect was established for an accurate detection of bevacizumab plasma concentration. Accordingly, this new assay was applied to bevacizumab PK studies in beagle dogs combined with a new PK model based on bevacizumab complex elimination. This assay was proved to be accurate and reproducible when bevacizumab concentrations were between 25 and 800 pg mL-1 with inaccuracy and imprecision below 15%. Moreover, the accuracy of the assay with control of the edge effect was significantly improved from the range of 98.61-134.01% to 104.81-105.89%, and the precision (relative standard deviation) was also improved from 13.10-37.90% to 3.60-5.45%. In the PK studies, bevacizumab nonlinear PK profiles were reasonably described with the new model based on bevacizumab complex elimination, and its fitting capacity was significantly improved compared to that of classic compartment models when the weighted residual sum of square of model fitting dramatically decreased. In conclusion, this new ELISA can control the influence of the edge effect, and it can play a major role in the PK studies of bevacizumab with the combined use of the new PK model.
No preview · Article · Oct 2015 · Analytical methods
[Show abstract][Hide abstract] ABSTRACT: A novel sensitive and selective LC-MS/MS method for the determination of agomelatine, 7-desmethyl-agomelatine and 3-hydroxy-agomelatine in human plasma was developed and validated. After simple protein precipitation, the analytes were separated on a Phenomenex ODS3 column (4.6×150 mm, 5μm, Phenomenex, USA) with mobile phase consisted of methanol and 5mM ammonium formate solution (containing 0.2% formic acid) at a ratio of 70:30 (v/v) with a flow rate of 0.8mL/min. The MS acquisition was performed in multiple reactions monitoring (MRM) mode with a positive electrospray ionization source. The mass transitions monitored were m/z 244.1→185.1, m/z 230.1→171.1, m/z 260.1→201.1 and m/z 180.1→110.1 for agomelatine, 7-desmethyl-agomelatine, 3-hydroxy-agomelatine and internal standard (phenacetin), respectively. The method was validated for specificity, linearity and lower limit of quantification, precision and accuracy, extraction recovery, matrix effect and stability. The calibration curves for agomelatine, 7-desmethyl-agomelatine and 3-hydroxy-agomelatine in human plasma were linear over concentration ranges of 0.0457-100ng/mL, 0.1372-300ng/mL and 0.4572-1000ng/mL, respectively. Intra- and inter-day precisions and accuracies data met the acceptance criteria of FDA guideline for bioanalytical method validation. The developed method has been successfully applied to a bioequivalence study in healthy Chinese volunteers.
Full-text · Article · Sep 2015 · Journal of chromatography. B, Analytical technologies in the biomedical and life sciences
[Show abstract][Hide abstract] ABSTRACT: The encapsulation of curcumin in whey protein microparticles by spray drying was done to improve solubility and thus, the bioavailability of curcumin. In solution, curcumin formed soluble complexes with whey protein isolate (WPI) via hydrophobic interactions and its solubility increased linearly with WPI concentrations. Solutions of WPI-curcumin complexes were spray-dried as uniform microparticles via a microfluidic jet spray dryer. Nearly 100% curcumin was retained in amorphous state and the microparticles could be easily rehydrated as transparent dispersions irrespective of the drying temperature. Antioxidant properties of these microparticles were studied by DPPH test, showing a higher DPPH radical scavenging activity for curcumin-loaded microparticles compared to that of WPI particles as benchmark. The ability to generate easily dissolved powders containing water-insoluble ingredients such as curcumin is a beneficial approach for pharmaceutical and functional foods applications.
[Show abstract][Hide abstract] ABSTRACT: Background:
The effects of the vascular endothelial growth factor (VEGF) gene -2578C/A polymorphism on colorectal cancer (CRC) risk have been investigated in some studies; however, the results of these studies were conflicting and ambiguous. Therefore, we aimed to do a meta-analysis to investigate the association of VEGF -2578C/A polymorphisms with CRC risk from all eligible case-control studies published to date.
Materials and methods:
An electronic search of the PubMed, Embase and Medline was performed. Retrieve terms were utilized as following: ("VEGF a" [MeSH Terms]) and ("polymorphism, genetic" [MeSH Terms]) and ("colorectal neoplasms" [MeSH Terms]). The association between VEGF -2578C/A polymorphisms with CRC risk was calculated with odds ratios (ORs) and their corresponding 95% of confidence intervals (CIs), and stratified analysis was also conducted with respect to ethnicity.
A comprehensive meta-analysis of eight studies, including 2312 cases and 2308 controls was performed in this work. Combined analysis revealed that a significant association between the VEGF -2578C/A polymorphism with CRC risk was identified in three comparison models including C allele versus A allele (OR = 0.85, 95% CI 0.75-0.97, P = 0.02), AA versus CA + CC (OR = 1.28, 95% CI 1.09-1.51, P = 0.003), and AA versus CC (OR = 0.77, 95% CI 0.64-0.93, P = 0.006). Moreover, a similar result was obtained in the subgroup analysis that comparison models of C allele versus. A allele (OR = 0.85, 95% CI 0.76-0.95, P = 0.004), AA versus CA + CC (OR = 1.31, 95% CI 1.09-1.57, P = 0.004), and AA versus CC (OR = 0.73, 95% CI 0.59-0.90, P = 0.004) was confirmed to be associated with CRC risk in Caucasian.
It has been proved that the C allele versus A allele, AA versus CA + CC, and AA versus CC comparison models of VEGF -2578C/A polymorphism might be risk factors for CRC, but further studies with larger sample sizes are required to make a better assessment of above association.
No preview · Article · Aug 2015 · Journal of research in medical sciences
[Show abstract][Hide abstract] ABSTRACT: Background:
Some studies have investigated the effects of polymorphisms in the vascular endothelial growth factor (VEGF) gene on responsiveness to chemotherapy for colorectal cancer (CRC) and have shown inconclusive results.
Eligible studies that assessed the associations between polymorphisms in the VEGF gene and response to chemotherapy in CRC were searched in the PubMed, Embase and Medline databases until November 2014. Odds ratios (OR) and 95% confidence intervals (CIs) were used to evaluate the associations, using Review Manager software, version 5.3. Stratified analysis was also conducted.
In the overall analysis, a significant association with responsiveness to chemotherapy in CRC was identified in CC vs. CA of the VEGF -2578 C/A polymorphism (OR = 1.40, 95% CI 1.00-1.97, P = 0.05) and in CC+CT vs. TT of the VEGF -460 C/T polymorphism (OR = 0.71, 95% CI 0.53-0.96, P = 0.02). In subgroup analysis, a significant association was found in excluding anti-angiogenic agent subgroup in three comparison models of the VEGF -2578 C/A polymorphism and another three genetic models of the VEGF -460 C/T C/A polymorphism.
CC vs. CA of the VEGF -2578 C/A polymorphism and CC+CT vs. TT of the VEGF -460 C/T polymorphism might be predictive factors of responsiveness to chemotherapy in CRC. However, single-nucleotide polymorphisms in the VEGF gene lacked sufficient predictive ability to determine whether patients with CRC should add anti-angiogenic agents to their chemotherapy regimens.
[Show abstract][Hide abstract] ABSTRACT: Conventional ways to produce microfluidic devices cost a lot due to the requirements for cleanroom environments and expensive equipment, which prevents the wider applications of microfluidics in academia and in industry. In this paper, a dry film photoresist was utilized in a simple way to reduce the fabrication cost of microfluidic masters. Thus, a fast prototyping and fabrication of microstructures in polydimethylsiloxane microchips through a replica molding technology was achieved in a low-cost setting within 2.5 h. Subsequently, major manufacturing conditions were optimized to acquire well-resolved microfluidic molds, and the replicated microchips were validated to be of good performance. A T-junction channel microchip was fabricated by using a dry film master to generate water droplets of uniform target size. Meanwhile, a gated injection of fluorescein sodium and a contactless conductivity detection of Na+ were both performed in a crosslink channel microchip via capillary electrophoresis, in other words, this fast prototyping and fabrication method would be an efficient, economical way to embody structural design into microfluidic chips for various applications.
Full-text · Article · Feb 2015 · Microsystem Technologies
[Show abstract][Hide abstract] ABSTRACT: IntroductionThe miR-183/-96/-182 cluster is a conserved polycistronic microRNA (miRNA) cluster which is highly expressed in most breast cancers. Although there are some sporadic reports which demonstrate the importance of each miRNA in this cluster in breast cancer, the biological roles of this cluster as a whole and its regulation mechanisms in breast cancer are still unclear. We compared the expression of this cluster in different cancer types, analyzed the regulation mechanism of this cluster, identified new target genes, and examined the impact of this cluster on breast cancer cells.Methods
The miRNA level was detected by LNA-based northern blot and Real-time PCR, and was also analyzed from TCGA dataset. Bioinformatics research and luciferase assay were applied to find the promoter regions and transcription factors. To investigate the biological effects of the miR-183/-96 /-182 cluster in breast cancer, we generated miR-96, miR-182 and miR-183 overexpression stable cell lines to check the overdose effects; we also used miR-Down¿ antagomir for each miRNA as well as miR-183/-96 /-182 cluster sponge lentivirus to check the knockdown effects. Growth, migration, cell cycle profile and survival of these cells was then monitored by colony formation assay, MTT assay, cell wound healing assay, flow cytometry and microscopy. The target gene was validated by Real-time PCR, luciferase assay, Western blot and Phalloidin/DAPI counterstaining.ResultsThe miR-183/-96/-182 cluster was highly expressed in most breast cancers, and its transcription is disordered in breast cancer. The miR-183/-96/-182 cluster was transcribed in the same pri-miRNA and its transcription was regulated by ZEB1 and HSF2. It increased breast cell growth by promoting more rapid completion of mitosis, promoted cell migration and was essential for cell survival. MiR-183 targeted the RAB21 mRNA directly in breast cancer.Conclusion
The miR-183/-96/-182 cluster is up-regulated in most breast cancer. It functions as an oncogene in breast cancer as it increases cell proliferation and migration.
Full-text · Article · Nov 2014 · Breast cancer research: BCR
[Show abstract][Hide abstract] ABSTRACT: The present study examined the agreement between in vitro dissolution f2 similarity and in vivo bioequivalence criteria for BCS class II drugs. Dissolution test profiles were generated using the First-order model with varied dissolution parameters around the standard values of a reference profile. The in vivo curves were derived from in vitro dissolution profiles with the drug's pharmacokinetics parameters by numerical convolution method. The Cmax, Tmax, AUC0-t and AUC0-∞ obtained from in vivo test and reference concentration-time curves were compared, and the CmaxR (Cmax ratio), TmaxDif (Tmax difference), AUC0-tR (AUC0-t ratio) and AUC0-∞R (AUC0-∞ ratio) were determined. The relationships between CmaxR, AUC0-tR, AUC0-∞R, f2 and the First-order model parameters demonstrated that the Similarity Region 1 enclosed by the f2 contour line labeled 50 was completely within the Bioequivalence Region enclosed by the contour lines labeled 0.80 and 1.20 of AUC0-tR, AUC0-∞R, and CmaxR, and the Similarity Region 2 enclosed by the f2 contour line labeled 35 was nearly overlapped with the Bioequivalence Region, but did not exactly match. The results indicate that the public standard for in vitro dissolution f2 similarity criterion (f2⩾50) is probably slightly conservative and may be widened to an appropriate lower critical value.
Full-text · Article · Oct 2014 · European journal of pharmaceutical sciences: official journal of the European Federation for Pharmaceutical Sciences
[Show abstract][Hide abstract] ABSTRACT: Unlabelled:
Defective autophagy is implicated in the pathogenesis of nonalcoholic fatty liver diseases (NAFLD) through poorly defined mechanisms. Cardiolipin is a mitochondrial phospholipid required for bioenergetics and mitophagy from yeast to mammals. Here we investigated a role for ALCAT1 in the development of NAFLD. ALCAT1 is a lysocardiolipin acyltransferase that catalyzes pathological cardiolipin remodeling in several aging-related diseases. We show that the onset of diet-induced NAFLD caused autophagic arrest in hepatocytes, leading to oxidative stress, mitochondrial dysfunction, and insulin resistance. In contrast, targeted deletion of ALCAT1 in mice prevented the onset of NAFLD. ALCAT1 deficiency also restored mitophagy, mitochondrial architecture, mitochondrial DNA (mtDNA) fidelity, and oxidative phosphorylation. In support of a causative role of the enzyme in a mitochondrial etiology of the disease, hepatic ALCAT1 expression was significantly up-regulated in mouse models of NAFLD.
Forced expression of ALCAT1 in primary hepatocytes led to multiple defects that are highly reminiscent of NAFLD, including steatosis, defective autophagy, and mitochondrial dysfunction, linking pathological cardiolipin remodeling by ALCAT1 to the pathogenesis of NAFLD.
[Show abstract][Hide abstract] ABSTRACT: Benfotiamine is a lipid-soluble thiamine precursor which can transform to thiamine in vivo and subsequently be metabolized to thiamine monophosphate (TMP) and thiamine diphosphate (TDP). This study investigated the pharmacokinetic profiles of thiamine and its phosphorylated metabolites after single- and multiple-dose administration of benfotiamine in healthy Chinese volunteers, and assessed the bioavailability of orally benfotiamine administration compared to thiamine hydrochloride. In addition, concentration of hippuric acid in urine which is produced in the transformation process of benfotiamine was determined. The results showed that thiamine and its phosphorylated metabolites exhibited different pharmacokinetic characteristics in plasma, blood and erythrocyte, and one-compartment model provided the best fit for pharmacokinetic profiles of thiamine. The transformation process of benfotiamine to thiamine produced large amount of hippuric acid. No accumulation of hippuric acid was observed after multiple-dose of benfotiamine. Compared to thiamine hydrochloride, the bioavailability of thiamine in plasma and TDP in erythrocyte after oral administration of benfotiamine were 1147.3 ± 490.3% and 195.8 ± 33.8%, respectively. The absorption rate and extent of benfotiamine systemic availability of thiamine were significantly increased indicating higher bioavailability of thiamine from oral dose of benfotiamine compared to oral dose of thiamine hydrochloride.
Full-text · Article · Jun 2014 · The Journal of Clinical Pharmacology